Remember, Budgie 10 is tightly based on GNOME, we already have, use, and rely on this GNOME stack. The core difference is that instead of having "lightdm", "budgie-desktop", and "budgie-desktop-branding" in the ISO definition file, we now have "gdm", "gnome-shell", "gnome-desktop-branding".
In terms of my time absorbed, it's actually about another 20 minutes when I do the public ISO snapshot, and it's not regular enough for that to be in any way a concern :)
We know lots of people in Solus have been using GNOME Shell for a long time, so we're now making that a first class experience (instead of some hybrid Budgie/GNOME Shell setup). For a long time we've been of the opinion that it's kinda silly *not* to have this GNOME Shell ISO.
We'll provide some testing ISOs to those of our Patrons interested in this, and value your feedback :)